A flexible or "flex" circuit is a laminate of flexible polyimide film, such as KAPTON.RTM., and a thin sheet of copper etched to produce a pattern of traces and contact pads. An overlying insulation layer is typically used to insulate the copper and environmentally seal the circuit. Flexible circuits include flexible flat cable (FFC) and flexible printed circuits (FPC). The FFC was originally designed as a compact and light-weight interconnect to replace bulky wire harnesses. With the advent of surface-mount electronic components, FPC technology evolved, creating a thin, flexible replacement for conventional rigid printed circuit boards. Flexible circuits provide multiple benefits. A flexible circuit can bend, fold, twist, and be rolled, providing almost unlimited freedom for locating parts and subassemblies. Further, the polyimide film can survive vibration and shock that would damage a rigid board. As a result, design engineers can utilize flexible circuits to solve space, configuration and weight problems that cannot be addressed with conventional wiring or rigid circuit technologies.